Electric motors and drive motors are increasingly constructed in modern motor vehicles. In this case, sometimes separately excited synchronous machines are used which have a rotor comprising a laminate stack provided with a field winding. In the case of such rotors, the individual pole teeth are separated from one another by slots. The field winding is accommodated in the slots.
During operation, very high centrifugal forces occur both in the case of internal rotors and in the case of external rotors, and these centrifugal forces can draw the field winding out of the slots. The centrifugal forces are dependent on the speed and on the weight of the slot-internal components. In particular in the case of high-speed machines, the winding is therefore secured after fitting. Various binders are known for this purpose which are used as impregnating resins or potting compounds. The potting of cavities in the rotor for reinforcing purposes is also known for permanent magnet rotors, for example from DE 10 2009 046 716 A1.
In addition, slot stoppers or slot wedges are sometimes used in order to prevent the winding from being withdrawn from the slot. In the case of rotors designed for electric motors with a very high speed (10 000 revolutions per minute or more), it would be desirable to secure the slot-internal components, in particular the field winding, even more effectively with respect to centrifugal forces occurring during operation.